Such a machine is known from the DE-AS 1 679 884. For this machine the kneading elements are designed as intermeshing kneading disks, which are usually provided with two or three axially extending edges. These relatively narrow kneading disks induce severe shear and thus intense development of heat in the material to be processed owing to the intermeshing of the kneading disks. Owing to the high shear concentrating on an axially relatively short region, the result is frequently high, temperature peaks, which involve the risk of thermal damage to the material concerned, when the operating parameters of the machine are not set and monitored especially accurately and carefully.